Second, you're ignoring the fact that life as we think of it can really only evolve around at least 3rd-generation stars because you need enough heavy elements. That cuts the age of the "life-capable" universe by at least half, so the window of relatively modern life on earth with respect to the age of the life-capable Universe really isn't that small... let's say 350My out of 7Gy, so about 5%.
This means that the star’s solar system at that point has sufficient quantities of heavy elements which cannot be produced by stellar fusion, as these elements are produced by super novae and from solar radiation.
Basically all the neutrons that are produced when a star goes boom create the elements that are above iron in the periodic table.
I suspect that the claim that life as we know it can only evolve there is because life as we know it needs a wide variety of chemical elements. We need carbon and oxygen, of course, but also iron and calcium and magnesium and potassium and so on. You're not going to get that around a first generation star. You might not get enough of it around a second generation star.
And most importantly first gen stars can’t form planets other than gas giants and even gas giants are questionable because our current understanding that other than a few failed stars these also usually require a heavy element core as a seed.
2nd gen stars are a possibility in a region of space that had a lot of 1st gen stars to nova and there might be sufficient amount of heavy elements already there to form a solar system.
So unless life can form from hydrogen, helium, lithium and beryllium then no life in 1st gen stars.
2nd gen is highly dependent on the region of space although I would posture that any region active enough to create sufficient amount of heavy elements would probably remain too active during the 2nd generation for life or at least complex life to form.
Due to our physical laws elements with larger rooms for reaction via chemistry are familar.
The chances of a replicating agent just anthropologically emerging from the surface of a 2nd generation hydrogen dominant star with an accumulation disc composed of little higher orders elements is inconceivably less likely than the relative petri dish organic molecules provide.
Regardless, the species is naturally incapable of averting averting crises that are foreseeable but distant.
Evolution has no agenda or goals, other than to select for survival. Most species on this planet have a low intelligence yet are successful, and don't seem to evolve into the direction of intelligence.
The preferred chirality of organic molecules could absolutely have arisen by chance, but it's an interesting to see this in meteorites.
On the unrelated subject of handedness, I saw an interesting thread on Twitter today [1] speaking about how we're starting to synthesize reverse chirality polymers and enzymes, most notably DNA and replication enzymes.
There are a lot of interesting implications.
You can't get rid of L-DNA without reverse DNase, leading to an accumulation of information and transcription. So they need to remake all the enzyme steroisomers.
That alone is interesting, but you can take it further to the limit and produce reverse biology that synthesizes reverse sugars that can't be metabolized by much of extant life [2]. Suddenly a lab-escaped reverse autotroph can out-compete all of us right-handed lifeforms because nothing can eat them. Bacteria, plankton, the entire food web collapses. When we have nothing left to fish or farm, we die too.
Never thought nanotech's grey goo was plausible. Now I see something that rhymes with it, and I could see it happening within our lifetimes.
It'd make a crazy MAD bioweapon on par with or potentially worse than nukes.
Wild tangent, sorry.
[1] https://twitter.com/eigenrobot/status/1420952351968432130
> Such negative values occurring shortly after the GOE require a rapid reduction in primary productivity of >80%, although even larger reductions are plausible. Given that these data imply a collapse in primary productivity rather than export efficiency, the trigger for this shift in the Earth system must reflect a change in the availability of nutrients, such as phosphorus. Cumulatively, these data highlight that Earth’s GOE is a tale of feast and famine: A geologically unprecedented reduction in the size of the biosphere occurred across the end-GOE transition.
But I assume they're not immune-invulnerable.
To be clear, evolution of viruses is probably inevitable. But on what time scale does it take for them to arrive ex nihilo? Millennia? Longer?
https://en.wikipedia.org/wiki/Microbial_metabolism
Water, sunlight, carbon sources, phosphorous sources, nitrogen sources. And any additional think they have enzymes to break down and process. Advanced organisms could feed off complex organic molecules, but this isn't necessary.
The point is that with reverse chiral sugars, polymers, etc., they wouldn't be a meal for anything in the wild. (At least not one with nutritional value.) No predation and no competition leads to massive expansion, and they could exhaust resources that other necessary parts of the food web require.
This would make a fantastic "phase one" alien bioweapon to aid in wiping out a planet's existing lifeforms and replace ecosystems with one better matching their own. Assuming post-biology aliens care about biology.
The first type is incidental: we've already encountered meteorites from Mars and the Moon, for example, so it's not hard to imagine life bearing material arriving that way.
The second would be intentional: either ET seeds planets or merely visits them with contaminated boots or probes.
Either way, we would pick up some DNA from offworld.
https://www.onezoom.org/life.html/@=111445?img=best_any&anim...
(hopefully that links to the right place)
There’s some speculation that a large amount of their genetics were transferred from other animals.[1] I wonder how much this muddles the tracing through the evolutionary tree.
If I recall correctly, the tardigrades (and extremophiles like D. radiodurans) have evolved to handle damage brought on by desiccation. As a fortunate side-effect, this general robustness also protects against radiation.
I'd do a life myself, I'd make it post-metallic, post-silicon, post static: I'd make it use water and carbon, so that it can exist everywhere. I would make it so that it can become intelligent on a small time scale, say a few billion years, all on its own, from scratch, on any rock :D
Not saying we have an engineer, but you think of engineered life as you are now as a simple software programmer. But an engineer in 500k years trying to expand more, would probably think of chemical automata that can evolve and adapt in harsh conditions. Say for instance if humanity decided it would be enjoyable for life to exist on Jupiter. It'd have to make something that can try a lot of variations with a very simple first formula to consume whatever gas there is there and survive whatever pressure.
Given the age of our universe, sun, earth and humans:
The probability of some alien life being within say, a range of [-.5 mllion, .5 million] of the life on earth is VERY slim. It is most likely that life out there is either in very early stages (protezoric) or that it is way farther than our current form (how will humanity look like in say, another 500,000 years?, assuming it continues to exist and evolve)